1. Field of the Invention
The present invention relates to a cuvette package, a method of loading multicell cuvettes packaged in such a package into a measurement instrument and a dispensing device for loading multicell cuvettes from said package according to the invention into measurement instruments having their cuvette dispensing means designed for packages that have been used earlier.
2. Description of the Related Art
For the assay of different liquids, analytic laboratories employ automatic analyzers in which the liquids to be assayed are placed in reaction vessels, designed to perform simultaneously as cuvettes of high optical quality. Generally, a row of reaction vessels or single-cell cuvettes may be combined into a multicell module of reaction vessels, separated from each other by a vertical wall and cast into a single-piece row. Herein, the reaction vessels are adapted side-by-side into an integral module with a common wall separating any two adjacent vessels and the long vertical sides of the multicell cuvettes made straight so that the multicell cuvettes in turn can be placed side-by-side into a contiguous row in which the long sides of the cuvettes are tightly adjacent to each other. Thus, the cuvettes can be stored in a rectangular container during transport and other handling. Such a multicell cuvette design is disclosed in U.S. Pat. No. 4,690,900. Cuvettes of the above-described type are easy to handle and give reliable measurement results.
In use, cuvettes must be kept free from dust, scratches and breakage so that the radiation passed in the analyzing instrument via the transmissive window surfaces of the reaction vessels would give reliable assay results. Hence, cuvettes must be treated with great care immediately after their manufacture in the subsequent packaging, storage, transport and measurement steps.
In the practical use of such cuvettes, a need has arisen for such a packaging method of cuvettes that can keep the cuvettes absolutely free from dust, scratches and fingerprint stains. While the packaging step ensuing the injection-moulding of the cuvettes can be performed fully controlled by automation methods and means, impact blows and human mishandling of the cuvette packages themselves during the loading of the cuvettes into the analyzing instrument have caused problems. To minimize such drawbacks, a cuvette packaging method has been developed in which the cuvettes are packaged into a row placed in a covered box with a removable cover. The mouth part of the package is shaped to fit into the cuvette intake port of the instrument, and the push lid of the package is provided with a pusher element for loading the cuvettes into instrument. When the package is attached to the cuvette intake port of the instrument, the cuvettes are transferred into the instrument by way of pushing the row of multicell cuvettes from behind with the help of the detachable push lid of the package, said lid incorporating a separate pusher element, which forms the other end of the package when the lid is still attached to the package. The benefits of this packaging method include dust-free handling, freedom from fingerprint contamination on the optical window areas of the cuvette or scratches of the same due to manual handling.
Such a box package has, however, some drawbacks which deteriorate its handling properties and increase packaging costs. The manufacture of the packaging box is costly in regard to the cost of cuvettes, whereby the unit price of assays will be increased by the expensive package. The discarded packages leave a great amount of plastic scrap to be transported to a dump or plastic materials recycling site. As the consumption of cuvettes in many laboratories has a high volume and the material of the packaging box may be different from the other plastic scrap resulting from the operation of the laboratory, this conventional arrangement is inferior in terms of recycling. Furthermore, the sorting and storage of cuvette packages in the laboratory spaces is clumsy. Since cuvettes are disposables and thus should not be recycled but as material, the cuvette package should contain the absolute minimum of material and the packaging materials should be easy to collect and recycle. While cuvettes in principle could be washed and reused, their optical window surfaces are extremely sensitive to contamination and mechanical damage. Therefore, cuvette manufacturers advise against reuse of cuvettes, because the risk of erroneous measurement results due to damaged/soiled cuvettes is high in the reuse of cuvettes.
Due to lower cost and material minimization, the cuvette packaging box must be made from thin material, whereby its rigidity is impaired. Resultingly, the box is readily warped and distorted as well as clumsy to use; the box and the cuvettes therein tilt easily, the cuvettes topple during their loading into the instrument and the box mouth cannot be held positively mounted on the cuvette intake port of the instrument. When fallen or tilted cuvettes are guided or erected manually, they are easily damaged by fingerprints or even scratches, which may cause erroneous measurement results. One problem hampering conventional packages is that the intake capacity of cuvette loading bays varies between different instrument makes, whereby also a varying number of excess cuvettes will always remain in the cuvette packages, and resultingly, the next batch of cuvettes must be loaded from two boxes in succession, whereby the number of incorrectly loaded cuvettes obviously will be higher.